Some information from official ECO-TEX SITE:
"If a textile article carries the STANDARD 100 label, you can be certain that every component of this article, i.e. every thread, button and other accessories, has been tested for harmful substances and that the article therefore is harmless for human health. The test is conducted by our independent OEKO-TEX® partner institutes on the basis of our extensive OEKO-TEX® criteria catalog. In the test they take into account numerous regulated and non-regulated substances, which may be harmful to human health. In many cases the limit values for the STANDARD 100 go beyond national and international requirements. The criteria catalog is updated at least once a year and expanded with new scientific knowledge or statutory requirements. "